Future networks are expected to support service upgrades to transmission rates of 100 Gb/s and beyond. Super-transponders (supporting multi-carrier super-channels) coupled with advanced multi-level modulation formats and bandwidth variable wavelength selective switches (BV-WSS) have become crucial elements for future spectral efficient networks. A super-channel represents an ultra high aggregate capacity channel carrying multiple sub-carriers which are co-routed through the network from the source to the destination.
Sub-carriers of a super-channel may require to be contiguous in the spectrum for technological reasons. Sub-carriers of a super-channel may or may not share a portion of spectrum resource with adjacent sub-carriers of the same super channel, i.e. they may or may not be superposed. A super-transponder is composed by a limited number M of sub-carriers. In the case that all the sub-carriers are activated, the super-channel experiences the maximum bit-rate. However, because of traffic dynamicity, the maximum bit-rate may be unnecessary and some sub-carriers may not be used (thus, possibly decreasing the power consumption), therefore not occupying network resources.